Is my Derasa in trouble?

[Mariner]

I've had it in my 75g tank for 9 or 10 months I guess. It's grown considerably and shows good color (for a Derasa ) Normally it stays wide open all day every day. But the last couple of days I've noticed it quickly closing/blowing a lot during the day -- as if it's trying to clear its tissues of some irritant. I noticed a couple of small places on its mantle that are kind of folded in -- look like they might have been nipped, but I'm not sure.
Anyway, I'm kind of concerned about it. I just read about Lunchbucket's loss, and I'm hoping I'm not headed down the same road.
Has anyone had a similar experience? Do these clams tend to recover from injury or irritants, or are they typically goners once they start having a problem?
Mariner

 

[mbbuna]

what fish do u have?
CA & ALK ok?
temp?
have u done anything new or different ?
can u post a few pics.

 

[Mariner]

Calcium is 410
Alk 9 dkh
temp 79
ammo, nitrite, nitrate all 0
Fish:
1 Regal/Hippo tang (the only potential nipper, IMO)
1 False perc
1 Mandarin
1 Brazilian Gramma
The only thing I'm doing different in the last few days is dosing a different brand of buffer. Switched from Kent Superbuffer to Seachem Reefbuilder. The Reefbuilder seems like it doesn't dissolve as well -- there are always a few small chunks no matter how much I stir. It's possible that a chunk or two could have landed on/near the clam.
I don't have a recent pic, but I'll try to get one.
Here's what the clam looked like back in October '04. Not a lot of change (other than some growth) from then till now, other than a couple of little places that look like they may have been nipped.

Mariner

 

[mbbuna]

r u using anything like ROWAPHOS orPHOSBAN forPO4?
every else seems good. the reason i ask is that i had a simular reaction with these products just recently.
it could also be the change in buffer,do u slow drip it or just mix and dump? do u mix it with seawater or RO/DI?

 

[Mariner]

No rowaphos or phosban,
I mix the Reefbuilder buffer with RO and pour it in. Went through a huge bottle of the Kent product with this procedure and had no problems -- but like I said, the Seachem doesn't seem to dissolve as well.
Here's a pic of the injured (?) clam mantle as of this morning. You can see a bit of the lower right mantle has either been nipped or just receded.

Mariner

 

[mbbuna]

it looks to me like the start of what people have been calling "pinched mantle" if it is there not much u can or should do right now.if it get's worse then u will have to do a freash water dip for 20 to 30 min. but i would wait and see if it clear's up on it's own for now. there has been a lot of debate about the cause of PM. first everyone thought it was high temp,now they think its a parasite. i lost 2 clams to a FWD so i would hold off for now.i still have some PM that seems to be clearing up on its oun,althou very slowly,been two month's, but there alive,with FWD they could be dead! TLC,and try to drip ur buffer

 

[Mariner]

mbbuna,
Great info. Thanks.
I guess my plan is to "wait and see" for now -- that's the plan I usually use with reef tank problems anyway
I'll post back here with any new developments.
Mariner

 

[Barry N.]

"pinched mantle"

Have never seen "pinched mantle" on a Tridacna derasa, mostly on Tridacna croceas

 

[Mariner]

Barry,
Any other thoughts/possibilities as to what might be going on?
thanks,
Mariner

 

[mbbuna]

Barry, please any input u have would be great.

 

[Peabody]

Have you checked at night for pyramid snails? I mean REALLY checked? Those suckers can be elusive

 

[Mariner]

Nope, haven't checked for pyramid snails.
I've heard of them, but don't know what they are or look like.
Anyone want to clue me in?
Mariner

 

[Barry N.]

what they are or look like.

They look like a grain of rice.

 

[kfisc]

Check the second photo- it looks as if you may have one just above the pinched area along the top of the shell- straight above the vermetid snail- nasty 'lil buggers, if it turns out to be one- good luck-

 

[Peabody]

I was thinking that looked like one too. Take the clam out several hours after dark. Remove any tiny snail, and be sure to check all around the mantle and byssal gland. Do this every night for a while!

 

[Mariner]

I looked early this morning -- didn't see any snails, but did find a small six armed starfish on the shell right next to the mantle. Don't know if he's the touble maker or just an innocent bystander, but he's gone.
Mariner

 

[Peabody]

Did you actually remove the clam and check for tiny, tiny snails all around and under the byssal opening? They can be hard to see unless you actually have the clam in your hands.

 

[Mariner]

Did you actually remove the clam and check for tiny, tiny snails all around and under the byssal opening?

Yep.
Will try again tonight.
Mariner

 

[Mariner]

Just an update on my clam.
It's doing very well. The injured places seem to be pretty well healed, and it's back to acting normally (for a clam )
Never found any snails.
Thanks to everyone who shared info, etc.
Mariner

 

[Peabody]

Glad to hear!!